Blown plastic container

ABSTRACT

This invention relates to a blown plastic container having an arcuate pressure bottom configuration, preferably provided with integrally formed multiple thickness support walls or &#39;&#39;&#39;&#39;skirts&#39;&#39;&#39;&#39; surrounding the bottom.

United States Patent 1191 Uhlig Oct. 22, 1974 [54] BLOWN PLASTICCONTAINER 3,511,401 5/1970 Lachner 215/1 c Inventor: Albert R. g, ToledoOhio 3,693,828 9/1972 Weussel et al 220/70 73 Assignee: Owens-Illinois,lnc., Toledo, Ohio FOREIGN PATENTS OR APPLICAT'ONS 1,175,048 12/1969Great Britain 215/1 C Flledi 1972 650,064 12/1962 ltaly 215/1 c N865,062 4/1961 Great Britain 2211/70 Primary Examiner-William 1. Price[3] :LS. Cll 215/1 C, 220/70, 264/89 Assistant Examiner stephen Marcus 1f C d 1/02 865d 1/40 365d 1/42 Attorney, Agent, or Firm-Philip M. Rice;E. J. Holler {58] Fneld of Search 215/1 C, 12 R; 220/68,

220/70 s [57] ABSTRACT [56] References Cited This invention relates to ablown plastic container UNITED STATES PATENTS having an arcuate pressurebottom configuration, pref- 1,461,729 7/1923 Foster et al 220/70 erablyprovided with integrally formed multiple thick- 2,54l,081 2/1951 Lyon220/70 n s support walls or skirts surrounding the bottom. 2,837,2456/1958 Grebowiec 215/1 C 3,059,810 10/1962 Edwards 229/15 B 5 Claims, 33Drawing Figures PAIENTED 03723974 3. 8-43 1. D05

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' sum 10 or 10 BLOWN PLASTIC CONTAINER The invention also contemplates amethod of making such containers by blowing the container in a blow moldhaving telescopically movable portions for physically contacting anddeforming a blowable parison or preform positioned in the blow mold. Theparison contact and deformation aids in forming the bottom and/or thesurrounding support walls, while providing a favorable blow-up ratioduring the blowing operation. Further, the method can be carried outunder conditions causing multi-axial orientation in the final container.

RELATED APPLICATIONS This application is related to the previously filedU.S. Pat. application Ser. No. 103,624, filed Jan. 4, 1971 in the nameof Albert R. Uhlig, entitled Method and Apparatus for Blow Molding, nowU.S. Pat. No. 3,767,747 and assigned to the Assignee of the presentinvention.

BACKGROUND OF THE INVENTION In the development of containers for theretention of liquid under pressure, for example carbonated beverages,beer and the like, it is desirable to provide the container with apressure bottom" configuration. Such bottoms are generally convex inconfiguration, although domed or concave configurations also areutilized. These bottom configurations generally avoid the sharp contourtransition portions located at the heels of a conventional flat-bottombeverage container, and, as a result, enhanced bottom strength in thecontainer is obtained.

This strength advantage is obtained in several ways. First, the designitself is simply better adapted to serve as a pressure vessel. Secondly,it is not necessary to move the plastic material, during blowing, intothe sharp bottom areas or heels of the container, with the inevitablethinning of the plastic material at the heels. Additionally, better walldistribution generally is obtained throughout the entire container, notonly at the bottom.

Containers having arcuate pressure bottom configurations suffer from oneprime disadvantage, i.'e., the convex bottom simply will not allow thecontainer to stand upright during filling, shipping, display or use.This problem has been solved in the past by utilizing separately formedskirts or angular support walls which are adhered to the bottom toprovide a support base. The cost of assembly, the utilization ofdisparate container and base materials, and the necessity of adhesiveapplication all have caused difficulties in the utilization of this typeof container.

BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention nowprovides a container, such as a beverage bottle or the like, forretaining fluid contents under pressure and having a pressure bottomsupport configuration including an arcuate bottom wall of either convexor concave configuration. The bottom wall is preferably provided with anintegrally formed, multiple thickness support structure or skirt locatedat the juncture of the container side walls and the container bottomwall. Since the preferred bottom wall pressure configuration iscircular, the support walls generally are annular in configuration andare conical to project downwardly and outwardly from the region ofbottom and side wall juncture to provide an enlarged support for thecontainer.

Thus, the support preferably consists of a pair of conical skirts formedintegrally, respectively, with the side wall and the bottom wall andjoined integrally to one another at their extremities. The skirts areadhered to one another, preferably by heat scaling, to provide themulti-thickness bottle support structure.

The method of the present invention includes the formation of thearcuate pressure bottom configuration by enclosing the parison orpreform from which the bottle is to be made interiorly of a blow moldwhich has telescopically movable parts, one of these parts having asurface defining the bottle bottom wall. During the blow moldingoperation, the one blow mold part is moved in contact with the preformbefore, during or after blowing to define the final shape of thepressure bottom.

In a preferred embodiment of the method of the present invention, thissame movement of the bottomdefining portion of the blow mold also aidsin forming the multithickness support wall. More specifically, thebottom wall-defining movement of the blow mold sur face also pinchestogether the support wall-defining portions of the container and heatseals them together.

OBJECTS bottom pressure wall is formed during blowing by tele- Iscopically moving a bottom-defining surface of the blow mold relative tothe remainder of the blow mold.

It is yet another, and no less important, object of the presentinvention to provide a method of making a blown plastic container in ablow mold having relatively movable sections and moving one of thesections into contact with a blowable shape enclosed in the blow mold todeform the blowable shape from its original configuration and thenblowing the blowable shape to its final article-defining configuration.

ON THE DRAWINGS FIG. 1 is a vertical sectional view of a bottle of thepresent invention made by the method of the present invention;

FIG. 2 is an exterior perspective view of the bottle of FIG. 1;

FIGS. 3 and 4 are views similar to FIGS. 1 and 2 of a different form ofbottle of the present invention;

FIGS. 5 and 6 are views similar to FIGS. 1 and 2 of an additional formof bottle of the present invention;

FIGS. 7 and 8 are views similar to FIGS. 1 and 2 of yet another bottleof the present invention;

FIGS. 9 and 10 are similar schematic views illustrating the method ofthe present invention as applied to the manufacture of the bottle ofFIGS. 1 and 2;

FIGS. 11 through 14 areviews similar to FIGS. 9 and 10 showing adifferent method of the present invention of manufacturing the bottle ofFIGS. 1 and 2;

FIGS. 15 through schematically represent the method steps carried out bythe present invention and the manufacture of the bottle of FIGS. 3 and4;

FIGS. 21-23, inclusive, illustrate schematically the method stepscarried out in the manufacture of the bottle of FIGS. 5 and 6;

FIGS. 24-29 illustrate schematically the steps carried out in themanufacture of the bottle of FIGS. 7 and 8; and

FIGS. 3032, inclusive, schematically illustrate the method steps carriedout in the manufacture of a modified bottle similar to that illustratedin FIGS. 3 and 4.

AS SHOWN ON THE DRAWINGS In FIGS. 1 and 2, reference numeral 40 refersgenerally to a bottle of the present invention made in accordance withthe method of the present invention. The bottle 40 is generallycylindrical in-configuration and, like the other bottles of the presentinvention, is integrally formed in one piece. More specifically, thebottle 40 includes an annular side wall 41 merging into and surmountedby an annular finish 42. The finish 42, as specifically illustrated, isadapted to receive a crimped beverage cap of the conventional type, butthe finish 42 may provide full or partial helical threads, or it mayreceive a snap-type cap, or may be modified as desired.

The side wall 41 merges into a lower, arcuate bottom wall 43 which isconcave in shape to lie wholly above the lower corner or heel 44 of thebottle. The arcuate bottom wall 43 is a pressure bottom in that itspartial spherical configuration resists pressure confined interiorly ofthe bottle.

The bottle of FIGS. 1 and 2 is manufactured as illustrated in FIGS. 9and 10 of the drawings. As shown in FIG. 9, a conventional, freelyextruded, tubular parison 45 is issued from an upper, downwardly openingannular extrusion orifice (not shown). This parison 45 is enclosedwithin a pair of preform mold sections 46 cooperatively defining aninterior preform mold cavity 47 of a configuration which more closelyapproaches the shape of the final bottle 40 than does the tubularparison 45. The mold sections 46 pinch shut the tubular parison 45,specifically pinching segments 48 carried by each mold section 46 engagethe tube and pinch it shut to form a tail 49 interposed between thepinch segments 48.

A blow head 50 is inserted into the open upper end of the parison 45,this blow head fitting snugly into the upper opening defined by theclosed mold sections 46 and engaging the tube free open upper end tohold it in place. Air under pressure is introduced through an axialopening 51 in the blow head 50 to inflate the tubular parison to theform of the preform cavity 47. It will be noted that the preform 52,after blowing, has a rounded,convex bottom, and this bottom is completedby actuation of the tail-pulling segments 48 downwardly, as is wellknown in the art.

The blown preform 52 now is transferred to a final blow mold 55comprising openable and closeable sec- I tions 55a and 55b whichcooperatively define an interior cavity 56 having the configuration ofthe finished article. It will be noted that each of these sections has asemi-cylindrical lower passage 57 within which is disposed acorrespondingly shaped mold bottom section 58, the sections 58 beingopenable and closeable with the respective sections 55a, 55b, whilebeing axially displaceable relative to the sections 55a and 55b. Thebottom sections 58 have their upper portions contoured at 58a, 58b in aconvex curve.

In the final blow molding operation carried out in the mold of FIG. 10,the preform is transferred to the mold by means of the blow pipe and themold sections a, 55b are closed thereon with the bottom sections 58 intheir retracted positions shown in dotted outline in FIG. 10. Afterclosure of the blow mold sections 55a, 55b on the preform, the bottommold sections 58 are actuated upwardly from their lowered positions intocontact with the convex bottom 55 of the preform, thus deforming thepreform upwardly to the concave configuration of the final bottle, asillustrated in solid outline in FIG. 10.

The advantages residing in the utilization of the technique illustratedin FIGS. 9 and 10 of the drawings and the manufacture of the finalbottle 40 of FIGS. 1 and 2 will be readily appreciated. Because of theconfiguration of the bottle, the attempted blowing of a cylindricalparison directly into the'final bottle shape necessitates the greatestinflation of the parison in the exact heel section of the bottle, withresultant bottom weakness.

By utilizing the telescopic bottom mold sections 58 in the blow moldsections 55a, 55b, it is possible to inflate the tubular parison intothe initial, gently curved convex bottom 53, and then mechanicallydeflect this bottom upwardly for blowing into its concave configurationas illustrated in FIG. 10. As a result a favorable blow-up ratio ismaintained, the heel portion of the bottle is of enhanced strength, andthe combination of physical deformation of the preform and blowing tofinal configuration results in a bottle of substantially constant wallthickness. The initial contact of the bottom mold sections 58 with theblown preform insures the maintenance of substantially the preform wallthickness throughout the bottom and heel portions of the finally blownbottle.

Of course, by the use of the preform blowing and subsequent finalblowing as carried out in the preform mold 46 and the final blow mold 55makes possible the final blowing at orientation temperature, asspecifically set forth and claimed in the above-identified US. Pat.application Ser. No. 103,624. As a result, all of the advantages setforth therein can also be obtained in the practice of the presentinvention.

Essentially the same type of bottom is made in accordance with thedisclosure of the modified method illustrated in FIGS. 11 through 14 ofthe drawings. In FIG. 11, it will be seen that the initial parison 59 isa freely extruded dependent tube which is enclosed within preform mold60 comprising mold sections 60a, 60b. The preform mold is substantiallythe same as that described in connection with FIG. 9, with the exceptionof an annular groove 61 cut into the cavity jointly defined by thepreform mold half 60a, 60b. This groove 61 encircles the cavity slightlyabove that portion of the cavity which is to define the convex preformbottom. Following inflation of the tube, the preform 62 results.

This preform has a convex bottom 63 which is encircled, slightly abovethe bottom thereof, by a rib 64 which has been formed in the groove 61.This rib forms, in essence, adjacent and reversely tapered conicalsurfaces.

Next, the preform tail is removed, as above explained in connection withFIG. 9 or by other suitable means, and the preform is transferred to afinal blow mold 65 illustrated in FIG. 12. The final blow mold 65comprises a pair of closeable and openable blow mold sections 65a and65b which cooperatively define an open ended interior mold cavity 66,the upper extremity of this mold cavity having a finish-defining recess67 therein, and the lower end of the blow mold being open, as at 68.

Telescoped over the blow mold sections 65a and 65b are separate,relatively movable mold bottom plates 69a and 69b, respectively, whichare movable laterally for opening and closing with the blow moldsections 65a, 65b, respectively. The bottom plates 69a are alsotelescopically movable axially relative to the blow mold sections 65a,65b when the blow mold sections 65a, 65b are forced downwardly under thethrust of the upper blow pipe 70.

This blow pipe 70 has an axial air opening 71 a lower conical portion 72and a peripheral shearing edge 73 located above the conical surface 72.Upon insertion of the blow pipe into the upper opening of the closedblow mold sections 65a, 65b, the blow pipe surface 72 and the shearingedge 73 reform the upper extremity of the preform 62 to the final finishconfiguration of the container, all as described in the above-identifiedUS. Pat. application Ser. No. 103,624.

Further, the downward thrust of the blow pipe 70 bottoms the moldsections 65a, 65b on the lower or bottom plate sections 69a, 69b. Theraised convex bottom-defining section 74 cooperatively defined by thebottom plate 69a, 69b contacts the lower extremity of the preform anddeflects the preform upwardly into the arcuate, concave bottom 75 of thefinished bottle 76 as illustrated in FIGS. 13 and 14. c

The location of the ribs 64 relative to the initial convex bottom 63 issuch that this rib 64 of double thickness encircles the bottom 75 of thefinished container 76 to provide a support surface for the final bottle.

Once again, the preform can be quite uniformly inflated without anythinning at the heel portion, the double thickness rib 64 circumscribingthe arcuate, concave bottom 75 is essentially formed during the preformblowing, and the bottom is reinforced by the multbthickness support wallprovided by the rib 64 at the juncture of the side walls and bottom wallof the final container 76.

Turning now to the bottle of FIGS. 3 and 4 of the drawings, the methodof making this bottle is illustrated in FIGS. I5 through 20, inclusive.

In FIG. 15, the initial formation of a preform 80 is illustrated, thispreform being made in separable preform blow mold sections 81, 82 whichcooperatively define a mold cavity 83 which is open at its upper andlower extremities. The lower extremities of the mold cavity 83 areclosed by separate bottom plates 84 which are carriedby the blow moldsections 81, 82 for transverse movement therewith, the plates 84pinching the initial parison therebetween to form the tail 85 as thetube is pinched shut.

The bottom plates 84 are also displaceable axially relative to the blowmold or preform blow mold sections 81, 82 as will be appreciated bycomparison of FIGS. 15 and 16. This displacement of the bottom plates 84can be carried out in any one of several ways. As illustrated, thedownward thrust of the blow pipe 86 after initial inflation of theinitial parison interiorly of the mold sections 81, 82 can be utilizedto telescopically force the preform blow mold sections 81, 82 downwardlyover the fixed bottom plate 84.

The blow pipe 86 is essentially the same as that illustrated anddescribed in connection with earlier embodiments of the invention. Frominspection of FIG. 15, it will be seen that the preform 80, as initiallyformed, reduces in cross-sectional configuration toward the bottomthereof to the point of juncture of the bottom of the finished containerand the side wall of the finished container, this narrowing of thepreform being indicated by reference numeral 87. Beneath the point 87,thepreform flares outwardly in a conical configuration, as at 88, andthis flared conical configuration merges into the reversely taperedconcave bottom 89 of the preform 80. Dimensionally, the transverse extent of the bottom plates 84 is somewhat less than the transversedistance between the points 87, the difference being less than twice thewall thickness of the preform 80.

Upon displacement of the preform blow molds 81, 82 relative to thebottom plates 84, the bottom 89 of the preform is displaced relativelyupwardly toward the points 87. The extent of displacement of the moldsections 81, 82 relative to the bottomplates 84, is such that the bottomwall 89 of the preform becomes aligned with the points 87 so as todefine a smooth, convex bottom for the parison 80. Contact between thestill hot plasticized material 89 of the bottom and this same materialat the points 87 under pressure exerted by relative movement of the moldsections and the bottom plates will heat seal the points87 to the bottom89 in the immediate vicinity of the outer corners of the bottom plates84 and completely around the points 87.

In effect, relative telescopic movement of the mold sections 81, 82 andthe bottom plates 84 has pinched shut the reversely tapered conicalportions 88 of the preform side wall and the bottom wall 89 at a pointabove the bottom extremity of the preform, thus forming double thicknessgenerally conical portions 96 on the preform. The reversely taperedportions 88 of the preform mold sections 81, 82 form recesses into whichthe pinched portions 96 of the preform are displaced outwardly bymovement of the bottom plates 84.

To complete the preform, as illustrated in FIG. 17 of the drawings, thethrust of the blow pipe 86 is relieved,

and the preform blow mold sections 81, 82 and the preform blow moldbottom plates 84 are moved relatively to return to their initialpositions of FIG. 15. This return of the preform blow mold parts isillustrated in FIG. 17. During such elevation of the blow molds 81, 82relative to the portions 84, the tail of the preform is removed.

Next, the finished preform 80 is transferred to a final blow moldindicated generally at 90 and consisting of two blow mold halves 90a,90b having an internal cav ity 91 which has the shape and size of thefinished bottle. Each blow mold half 904: carries a bottom plate 92movable transversely for opening and closing movement with itsrespective mold half 90a, 90b, and axially displaceable relative to itsrespective mold half. Each such bottom plate 92 is provided with anupper arcuate recess 93, the recesses cooperatively defining the contourof the bottom of the finished bottle. Further, each mold bottom plate 92has an exterior semi-conical side surface 94 cooperable with taperedside surfaces 95 of the blow mold sections 90a, 90b underlying the blowmold recess 91 and communicating therewith. The tapered blow mold halfsurfaces 95 are adapted to receive therebetween the pinched portions 96of the preform 80, which had been previously formed as above described.

The contour and size of the blow mold cavity 91 is such that the preform80, when disposed interiorly of the cavity 91 as illustrated in FIG. 18of the drawings rests on the lower annular lip 97 of the cavity 91located at the juncture of the cavity 91 with the tapered surfaces 95.

Next, a blow pipe 86A similar-to the blow pipe 70 earlier described inconnection with the embodiment of the invention shown in FIG. 12 of thedrawings, is inserted into the open upper end of the preform 80, and theblow pipe thrusts the blow mold sections 90a, 90b downwardly relative tothe bottom plates 92. This relative motion between the mold sections90a, 90b and the bottom plates 92 contacts the upper arcuate surfaces 93of the plates 92 with the bottom of the preform, and the taperedsurfaces 94 on the plates 92 coact with the tapered surfaces 95 on theblow mold sections to urge together under pressure the previouslypinchedportions 96 of the preform. This operation is illustrated in FIG. 19 ofthe drawings. Next, air under pressure is introduced through the blowpipe 86A to inflate the preform to the exact configuration of the finalbottle as determined by the mold cavity 91 and the upper arcuatesurfaces 93 of the bottom plates 92. Of course, the blow pipe alsoreforms and finishes the finish 98 of the bottle at the same time asabove described and also as described in greater detail in myabove-identified pending application.

The mechanical deformation and pressuring of the previously pinchedportions 96 results in the formation of a double thickness conicalbottom support wall 99 for the finished container 100, the twothicknesses of plastic forming the support wall 99 being heat sealedtogether throughout substantially their entire length. In essence, thissupport wall is defined by the formation of the two outwardly flaring,generally conical, peripheral skirts during the pinching together ofportions of the preform as above described in connection with FIGS. 16and 17 followed by the final pressing carried out by the method stepillustrated in FIG 19. One of these skirts is formed integrally with theside wall of the container and the other of these skirts is formedintegrally with the bottom wall of the container, and these skirts arejoined integrally to one another at their bottom extremities, since theplastic is merely folded back upon itself during formation of theskirts.

It has been found that heat sealing at relatively low temperatures, eg220 F or greater, is possible for most thermoplastic resins utilized inpressure'containers, such as polyvinyl chloride and polyethylene. Solong as the operation of FIG. 19 is carried out while the temperature isabove its minimum heat sealing temperature, the formation of themultiple thickness support wall 99 will be possible.

From the description already given, the structure of the bottle 100 asillustrated in FIGS. 3 and 4 of the drawings will be evident.

Turning now to the bottle illustrated in FIGS. 5 and 6 of the drawings,it will be seen that this bottle is of somewhat different configurationthan those earlier described. More particularly, this bottle comprises amain body portion of generally cylindrical configuration and having anupper finish indicated generally at 111. Again, the finish configurationcan be as desired to receive an appropriate cap.

The bottom of the bottle is convex, as illustrated at 112, and thebottom 112 has an integrally formed, generally dependent, but slightlyoutwardly flaring conical support surface 113 integrally joined, as at114, to a similarly tapered and conical support wall 115 formedintegrally with the side walls 116 of the container. The exteriorsurface of the interior wall 113 is heat sealed or otherwise adhered tothe inner surface of the outer wall 115, thereby providing a multiplethickness bottom support for the bottle and permitting utilization ofthe convex, pressure resistant configuration of the bottle bottom 112.

The method of formation of the bottle of FIGS. 5 and 6 is illustrated inFIGS. 21-23, inclusive, of the drawings.

In FIG. 21, a preform 120 has been previously formed by blowing aparison to shape. This preform generally is formed in the same way asthe preform is blown in FIG. 9 of the drawings previously described. Thepreform 120 has its side walls 121 joined to its convex bottom wall 122by a hinged joining portion 123. This hinged joining portion 123 isjoined to the side walls 121 by means of a peripheral external bead 124immediately underlying conically outwardly flaring side wall portions125 which will become the outer support wall 115 in the final container.The hinged wall 123 will become the inner support wall 113 in the finalcontainer, and this hinged portion 123 is joined to the bottom 122 by aninwardly projecting bead 126.

The preform 120 is suspended interiorly of separable blow mold halves127, 128 having an upper finishdefining opening 129 and a lower opening130 generally aligned laterally with the upper outwardly directed bead124. Separate bottom plates 131, 132 are provided for each mold half127, 128, respectively, these bottom plates 131, 132 being laterallyseparable with the mold halves, yet independently axially displaceablerelative thereto. Each mold bottom plate 131, 132 has a concave uppersurface 133 for contacting the bottom 122 of the preform 120.

Outwardly and downwardly flaring semi-conical surfaces 134 are providedon each mold bottom plate 131, 132 for contacting the fold portion 123of the preform 120 and generally parallel, downwardly and outwardlyflaring semi-conical portions 135 are provided in each blow mold half127, 128 for contacting the portions 125 of the preform 120.

Initially, a blow tube 136 is brought down into position to close theopen upper end 129 of the blow mold halves 127, 128 and to clamp theupper end of the preform 120 in position relative to the mold halves127, 128. At the same time, this blow pipe 136 reforms the finish of thecontainer in the manner described previously in this application anddescribed in detail in my above-identified earlier pending patentapplication.

upwardly, the hinge 126 overlapping the edges of the bottom platesupport surfaces 133, so that the bottom plate surfaces 134 contact theexterior of portion 123 of the preform. As the bottom plates 131, 132move relatively upwardly, the portion 123 is contacted at its exteriorsurface by the surfaces 134 and the conical portions 125 of the preformare moved outwardly into contact with the mold half surfaces 135. At thesame time, blow air is introduced through the blow nozzle 136, and thepreform is inflated against the cavity of the blow mold halves 127, 128.

Thus, telescopic movement of the mold parts folds and then pinchestogether those portions of the preform located immediately above thebottom portion 122 of the preform at the same time that the bottomportion 122 of the preform is being elevated. As a result, the surfaces134, 135 urge the preform portions 123 and 125 into surface abutment forheat sealing together to form the multiple thickness support wallsurrounding and supporting the bottom 112 of the final container.

Turning now to that form of bottle illustrated in FIGS. 7 and 8 of thedrawings, it will be seen that the bottle 139 includes side walls 140surmounted by a finish 141 of any desired type. The side walls 140 flareoutwardly to conical support walls 143 at their lower extremity which isjoined integrally at 144 to an interior, domed, concave bottom wall 142.The domed bot,- tom wall 142 is a semi-spherical in shape, so that thelower extremities 145 of the bottom wall 142 are generally axiallyconical in configuration, as will be hereinafter explained in detail,and the conical portions 145 of the bottom 142 and 143 of the side wall140 are heat sealed together to provide a multiple thickness supportwall for the bottom.

The method of manufacturing the bottle 139 of FIGS. 7 and 8 isillustrated in FIGS. 24 through 29.

As illustrated in FIG. 24, the initial step in the manufacture of thebottle 140 of FIG. 7, involves the extrusion of a tubular initialparison 147 from an overhead, downwardly directed orifice block 146, theparison being cut from the extrudate issuing from the nozzle 146 by aknife 148 in a manner well known in the prior art.

Prior to severing by the knife 148, the preform blow mold 150 is movedinto surrounding position with the parison 147, the blow mold halves150a, and l50b being closed on the parison, also in a manner well knownin the prior art. The parison mold halves 150a and Gb carry at theirlower extremities a pair of pinching elements 154 which are openable andcloseable with the blow mold sections, but relatively axially movable,as earlier described and as known in the prior art.

The blow mold halves 1500, 150b define an interior preform blow moldcavity 151 which is of a shape intermediate the shape of the initialtubular parison 1.47 and of the final bottle 140. This mold cavity 151includes a peripheral recess or groove 152 located intermediate sidewall-defining portions of the cavity 151 and the bottom-defining portion153 of the cavity 151. It will sure of the blow molds, the pinchingportions 154 thereof pinch shut the parison 147, the lower pinchedportion or tail 1550f the parison thus being located completely outsidethe confines of the preform cavity 151.

As illustratedin FIG. 25, the next step involves the insertion of a blowpipe 156 into the open, upper cut end of the parison 147 and theintroduction of blow air through this blow pipe into theinterior of theparison 147. The parison 147 thus is inflated into the blown preform 157having a peripheral bead or rib 158 encircling the preform intermediatethe side walls and the bottom 159 thereof. It will be noted that thisrib 158 is of an axial and radial extentsuch that the rib actually isdefined by a pair of oppositely tapering, conical rib walls. I

Following the inflation of the parison 147 into the preform 157, thetail removal elements 154 are actuated downwardly to sever the tail fromthe blown preform 157. Next, the preform blow mold sections 1500, 15012are opened and the preform, retained by the blow pipe 156, is removedfor subsequent-processmg.

As illustrated in FIGS. 27 through 29, the preform 157 is transferred toa final blow mold 160. consisting of blow mold halves 160a, 16% whichare openable and closeable transversely, the blow mold halves beingillustrated in their closed position in FIG. 27 and in their openposition in FIG. 29. l

The blow mold halves 160a, 160b, when closed, de fine .a cavity whichgenerally conforms to the shape of the bottle 140 which is opened at:its upper end 161 and which is opened at its lower end as at 163. Theblow mold halves 160 terminate short of the overall length of thepreform 157, the bottom open end 163 of the blow mold halves 1600, 160kbeing located immediately adjacent the location of the rib 158 of thepreform 170 and above the bottom 159 of the preform. Each of the blowmold halves 160a, 160!) carries a bottom plate indicated generally at164, these bottom plates being movable transversely for opening andclosing movement with the blow mold halves 160a, l60b. The bottom plates164 also are movable vertically (axially of the preform 157) relative tothe mold halves 160a, 1601). More specifically, these bottom plates 164each have a spherical surface 165 located centrally of the completedblow mold 160 and conforming generally to the shape of the bottom 142 ofthe finished container and merging through a conical surface 169 into abottom recess 166 adapted to receive the lower open end of theassociatedblow mold segment 160a, 16%. A cylindrical verticalguidesurface 167 projects upwardly from the recess 166 on the exterior sidethereof for guiding vertical movement of the bottom plates 164 relativeto the blow mold sections 160a, 16%.

During the blowing operation, a blow nozzle 170 is inserted into theopen upper end of the preform 157. This blow pipe 170 has a conicalsurface 171 insertable into the open end of the preform 157 and afinishdefining recess 172 which is cooperable with the upper end of theblow mold to define the final finish 144 of the bottle 140. The blowpipe has a passage 173 for the flow of air under pressure theretlhroughto inflate the preform to its final configuration.

As illustrated in FIG. 28, the thrust of the blow pipe 170 against theopen upper end of the blow mold 160 telescopes the blow mold downwardlyrelative to the bottom plates 164 with the lower open end of the blowmold halves 160a, 160b entering the recesses 166. During such telescopicmovement, the partial spherical surfaces 165 of the bottom plates 164contact the bottom 159 of the preform 157 and deform the bottom 159upwardly to the concave configuration of the final bottom wall 142. Thisupward movement of the preform bottom wall 159 actually hinges thebottom wall 159 around the peripheral rib 158 of the preform 157 whichis located at the juncture of the blow mold halves 160a, 16% and thebottom plate 164. During the completion of the telescopic movement, thefrustoconical wall section 168 recessed at the lower ends of the blowmold halves contact the exterior of the preform immediately above therib 158, while the conical surfaces 169 immediately adjacent thejuncture of the partial spherical surface 165 at the bottom of therecess 166 contacts the exterior surface of the preform bottom wall 159immediately below the rib 158.

As illustrated in FIG. 28A, the surfaces 168, 169 are of slightlydifferent slope and, when fully telescoped, the surfaces approach oneanother upwardly to pinch shut the bottom support wall portions 143, 145earlier described in connection with FIGS. 7 and 8.

The material which originally constituted the peripheral rib 158 of thepreform 157 constitutes the lower joining portion 144 at the extremelower end of the container, this material simply being folded uponitself to form the integral juncture between the walls 143, 145. Sincethe surfaces 168, 169 force the material into extended surface contactand the material is still hot, the walls 143, 145 are heat sealed orheat welded together to form the multiple thickness bottom wall supportfor the container 140.

Finally, the blow mold sections 160a, l60b are opened as the blow pipe170 is retracted upwardly, and the final bottle 140 is released asillustrated in FIG. 29.

It will be noted that in each method of manufacturing a bottleheretofore described in conjunction with the previously illustratedembodiments of the present invention, utilized a preform blowing step.The method may also be adapted to form a bottle without such anintermediate or preforming step. This method is illustrated in detail inFIGS. 30-32, inclusive. This form of bottle formed by the method ofFIGS. 30-32 is illustrated in FIGS. 3 and 4, but the method can beadapted to other bottles as well.

In further detail, FIG. 30 illustrates the closure of a blow mold 180 ona tubular parison illustrated in dotted outline at 181 to pinch the tubeshut and form a blowable shape therefrom.

More specifically, the blow mold 180 comprises a pair of blow moldhalves or sections 180a, 18% which are laterally closeable onto theextrudedparison 181. The blow mold cavity 182 defined by the blow mold180 includes an upper finish-defining portion 183, and intermediate sidewall defining portion 184 terminating in a lower, inwardly directed rib185 overlying a lower cylindrical recess 186. The rib 185 has apartially spherical upper surface 187 which merges into the sidewall-defining portion 184 of the associated blow mold half 180a, 180band which partially defines the bottom of the finished container. Theunder surface of the rib,

as illustrated at 188, is conical in configuration to define a portionof the bottom support wall 99 of the container illustrated in FIGS. 3and 4.

Positioned in each of the semi-cylindrical recesses 186 of the moldhalves a, 1801) is a pair of tail pinching elements 190, these elementsbeing transversely movable with the associated blow mold halves andbeing axially or vertically movable relative thereto as has been abovedescribed. The upper surface of each of the tail elements 190 is arcuatein contour to smoothly blend into the bottom-defining wall portion 187of the associated blow mold cavity 182. The radially outer portion ofeach of the tail pulling element 190 underlies the rib on the associatedconical surface 188. The outer portion 192 of each tail pulling elementhas a conical configuration which lies parallel to the surface 188 andin axially spaced relation thereto, when the tail elements 190 arepositioned as illustrated in FIG. 30.

Also, as shown in FIG. 30, the parison 181 is inflated by means of ablow pipe 194 inserted into the open upper end of the parison andcooperating with the finish-defining portions of the blow mold sections180a, 18% to define the finish of the bottle as has been heretoforedescribed. Upon inflation of the pinched-shut parison, the parison isblown outwardly against the walls of the blow mold sections 180a, 18017,the parison extending outwardly into contact with the side walldefiningportions 184, the partial bottom defining portions 187, the conicalportions 188, 192, and the short cylindrical length of the recess186,-all as illustrated in FIG. 30.

While the parison is still hot and after its inflation, the tailelements 190 are actuated relatively upwardly with respect to the blowmold sections 180a, l80b as will be seen from a comparison of FIGS. 30and 31. Preferably, this motion is accomplished under the thrust of theblow tube 194. Such relative movement of the tail portions 190 and theblow mold sections will bring the portions of the blown preformcontacting the bottomdefining surfaces 190 into registry with thesurfaces 187 of the blow mold sections to define the smooth convexbottom of the final container. Such movement also will bring intoabutment those portions of the blown parison contacting the conicalsurfaces 188, 192 and these surfaces will be heat welded into contact todefine the multi-thickness bottom support wall under lying the bottom ofthe finished container.

Next, the blow molds are retained in their position'of FIG. 30 untilsuch time as the heat welding or heat sealing of the bottom-definingportions has been completed, then the tail sections 190 are movedrelatively downwardly with respect to the blow mold sections 1800, 180b,thereby removing the tail from the finished container.

Next, the mold halves 180a, 180k are laterally separated and the blowpipe 194 is retracted upwardly to release the finished container.

I claim:

1. In a blown plastic container having a finish and integralside walls,the improvement of an integral pressure bottom support configurationincluding an arcuate bottom wall integral with said side walls, anoutwardly flaring peripheral skirt integral with said bottom wall, and asecond outwardly flaring peripheral skirt integral with said side walland encompassing the skirt of said bottom wall, said skirts being joinedintegrally to one another at their bottom extremities to form a supportedge for said container and skirts being integrally and continuouslyheat sealed to one another adjacent said support edge to define amultiple thickness support wall, said side walls, said bottom wall andboth of said skirts having the same thermal history.

2. In a container as defined in claim 1, the further improvement whereinsaid bottom wall is convex and the bottom wall skirt is conical tosurround the bottom wall and project therebelow, the bottom wall andskirt being joined integrally to one another at the outer periphery ofthe bottom wall, and the second skirt also is conical and is in surfacecontact with the outer surface of the bottom wall skirt throughoutsubstantially the entire length of said bottom wall skirt.

3. In a container as defined in claim 1, the further improvement whereinsaid bottom wall is concave to liev wholly above both the skirts, andthe skirts are each conical and in limited contact with one anotherimmediately adjacent said annular support edge.

4. A one-piece blown plastic container, comprising axially spaced finishand bottom portions joined by an 7 annular side wall, said bottomportion including an arcuate bottom wall joined integrally to said sidewall through an outwardly flaring conical skirt terminating in anannular support edge underlying said bottom, said skirt, bottom wall andside wall all having the same thermal history, said side wall having aconical lower portion formed integrally therewith and joined to saidskirt at said support edge, said skirt encompassing said lower portionand in contact therewith adjacent said edge, the contracting portions ofsaid bottom being adhered to one another to form an integrally andcontinuously fused double thickness support base underlying said bottomwall.

5. A one-piece plastic container formed as an article of rotation aboutan axis and comprising integral finish side-wall and bottom-wallportions, all having the same thermal history said bottom wall beingarcuate and circumscribed by a depending skirt the bottom annular edgeof which forms the one axial extremity of said container, the side wallalso having a depending portion which terminates in an annular edgecoextensive with and integral with said skirt edge, said side wallportion encompassing said skirt in surface contact therewith adjacentsaid edge, the contacting portions of said side wall portion and saidskirt being continuously and integrally adhered together to form :anannular, multiple thickness bottom support for said container.

1. In a blown plastic container having a finish and integral side walls,the improvement of an integral pressure bottom support configurationincluding an arcuate bottom wall integral with said side walls, anoutwardly flaring peripheral skirt integral with said bottom wall, and asecond outwardly flaring peripheral skirt integral with said side walland encompassing the skirt of said bottom wall, said skirts being joinedintegrally to one another at their bottom extremities to form a supportedge for said container and skirts being integrally and continuouslyheat sealed to one another adjacent said support edge to define amultiple thickness support wall, said side walls, said bottom wall andboth of said skirts having the same thermal history.
 2. In a containeras defined in claim 1, the further improvement wherein said bottom wallis convex and the bottom wall skirt is conical to surround the bottomwall and project therebelow, the bottom wall and skirt being joinedintegrally to one another at the outer periphery of the bottom wall, andthe second skirt also is conical and is in surface contact with theouter surface of the bottom wall skirt throughout substantially theentire length of said bottom wall skirt.
 3. In a container as defined inclaim 1, the further improvement wherein said bottom wall is concave tolie wholly above both the skirts, and the skirts are each conical and inlimited contact with one another immediately adjacent said annularsupport edge.
 4. A one-piece blown plastic container, comprising axiallyspaced finish and bottom portions joined by an annular side wall, saidbottom portion including an arcuate bottom wall joined integrally tosaid side wall through an outwardly flaring conical skirt terminating inan annular support edge underlying said bottom, said skirt, bottom walland side wall all having the same thermal history, said side wall havinga conical lower portion formed integrally therewith and joined to saidskirt at said support edge, said skirt encompassing said lower portionand in contact therewith adjacent said edge, the contracting portions ofsaid bottom being adhered to one another to form an integrally andcontinuously fused double thickness support base underlying said bottomwall.
 5. A one-piece plastic container formed as an article of rotationabout an axis and comprising integral finish side-wall and bottom-wallportions, all having thE same thermal history said bottom wall beingarcuate and circumscribed by a depending skirt the bottom annular edgeof which forms the one axial extremity of said container, the side wallalso having a depending portion which terminates in an annular edgecoextensive with and integral with said skirt edge, said side wallportion encompassing said skirt in surface contact therewith adjacentsaid edge, the contacting portions of said side wall portion and saidskirt being continuously and integrally adhered together to form anannular, multiple thickness bottom support for said container.